//===========================================================================
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//===========================================================================
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//
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//
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// e_cosh.c
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// e_cosh.c
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//
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//
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// Part of the standard mathematical function library
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// Part of the standard mathematical function library
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//
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//
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//===========================================================================
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//===========================================================================
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//####ECOSGPLCOPYRIGHTBEGIN####
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//####ECOSGPLCOPYRIGHTBEGIN####
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// -------------------------------------------
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// -------------------------------------------
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// This file is part of eCos, the Embedded Configurable Operating System.
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// This file is part of eCos, the Embedded Configurable Operating System.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
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//
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//
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// eCos is free software; you can redistribute it and/or modify it under
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// eCos is free software; you can redistribute it and/or modify it under
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// the terms of the GNU General Public License as published by the Free
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// the terms of the GNU General Public License as published by the Free
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// Software Foundation; either version 2 or (at your option) any later version.
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// Software Foundation; either version 2 or (at your option) any later version.
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//
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//
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// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
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// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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// for more details.
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// for more details.
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//
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//
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// You should have received a copy of the GNU General Public License along
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// You should have received a copy of the GNU General Public License along
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// with eCos; if not, write to the Free Software Foundation, Inc.,
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// with eCos; if not, write to the Free Software Foundation, Inc.,
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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
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//
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//
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// As a special exception, if other files instantiate templates or use macros
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// As a special exception, if other files instantiate templates or use macros
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// or inline functions from this file, or you compile this file and link it
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// or inline functions from this file, or you compile this file and link it
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// with other works to produce a work based on this file, this file does not
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// with other works to produce a work based on this file, this file does not
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// by itself cause the resulting work to be covered by the GNU General Public
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// by itself cause the resulting work to be covered by the GNU General Public
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// License. However the source code for this file must still be made available
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// License. However the source code for this file must still be made available
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// in accordance with section (3) of the GNU General Public License.
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// in accordance with section (3) of the GNU General Public License.
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//
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//
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// This exception does not invalidate any other reasons why a work based on
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// This exception does not invalidate any other reasons why a work based on
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// this file might be covered by the GNU General Public License.
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// this file might be covered by the GNU General Public License.
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//
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//
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// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
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// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
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// at http://sources.redhat.com/ecos/ecos-license/
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// at http://sources.redhat.com/ecos/ecos-license/
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// -------------------------------------------
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// -------------------------------------------
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//####ECOSGPLCOPYRIGHTEND####
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//####ECOSGPLCOPYRIGHTEND####
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//===========================================================================
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//===========================================================================
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//#####DESCRIPTIONBEGIN####
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//#####DESCRIPTIONBEGIN####
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//
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//
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// Author(s): jlarmour
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// Author(s): jlarmour
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// Contributors: jlarmour
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// Contributors: jlarmour
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// Date: 1998-02-13
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// Date: 1998-02-13
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// Purpose:
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// Purpose:
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// Description:
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// Description:
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// Usage:
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// Usage:
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//
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//
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//####DESCRIPTIONEND####
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//####DESCRIPTIONEND####
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//
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//
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//===========================================================================
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//===========================================================================
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// CONFIGURATION
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// CONFIGURATION
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#include <pkgconf/libm.h> // Configuration header
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#include <pkgconf/libm.h> // Configuration header
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// Include the Math library?
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// Include the Math library?
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#ifdef CYGPKG_LIBM
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#ifdef CYGPKG_LIBM
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// Derived from code with the following copyright
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// Derived from code with the following copyright
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/* @(#)e_cosh.c 1.3 95/01/18 */
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/* @(#)e_cosh.c 1.3 95/01/18 */
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/*
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/*
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* ====================================================
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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*
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* software is freely granted, provided that this notice
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* is preserved.
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* is preserved.
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* ====================================================
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* ====================================================
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*/
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*/
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/* __ieee754_cosh(x)
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/* __ieee754_cosh(x)
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* Method :
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* Method :
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* mathematically cosh(x) if defined to be (exp(x)+exp(-x))/2
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* mathematically cosh(x) if defined to be (exp(x)+exp(-x))/2
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* 1. Replace x by |x| (cosh(x) = cosh(-x)).
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* 1. Replace x by |x| (cosh(x) = cosh(-x)).
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* 2.
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* 2.
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* [ exp(x) - 1 ]^2
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* [ exp(x) - 1 ]^2
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* 0 <= x <= ln2/2 : cosh(x) := 1 + -------------------
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* 0 <= x <= ln2/2 : cosh(x) := 1 + -------------------
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* 2*exp(x)
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* 2*exp(x)
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*
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*
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* exp(x) + 1/exp(x)
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* exp(x) + 1/exp(x)
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* ln2/2 <= x <= 22 : cosh(x) := -------------------
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* ln2/2 <= x <= 22 : cosh(x) := -------------------
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* 2
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* 2
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* 22 <= x <= lnovft : cosh(x) := exp(x)/2
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* 22 <= x <= lnovft : cosh(x) := exp(x)/2
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* lnovft <= x <= ln2ovft: cosh(x) := exp(x/2)/2 * exp(x/2)
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* lnovft <= x <= ln2ovft: cosh(x) := exp(x/2)/2 * exp(x/2)
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* ln2ovft < x : cosh(x) := huge*huge (overflow)
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* ln2ovft < x : cosh(x) := huge*huge (overflow)
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*
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*
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* Special cases:
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* Special cases:
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* cosh(x) is |x| if x is +INF, -INF, or NaN.
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* cosh(x) is |x| if x is +INF, -INF, or NaN.
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* only cosh(0)=1 is exact for finite x.
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* only cosh(0)=1 is exact for finite x.
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*/
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*/
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#include "mathincl/fdlibm.h"
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#include "mathincl/fdlibm.h"
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static const double one = 1.0, half=0.5, huge = 1.0e300;
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static const double one = 1.0, half=0.5, huge = 1.0e300;
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double __ieee754_cosh(double x)
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double __ieee754_cosh(double x)
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{
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{
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double t,w;
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double t,w;
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int ix;
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int ix;
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unsigned lx;
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unsigned lx;
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/* High word of |x|. */
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/* High word of |x|. */
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ix = CYG_LIBM_HI(x);
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ix = CYG_LIBM_HI(x);
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ix &= 0x7fffffff;
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ix &= 0x7fffffff;
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/* x is INF or NaN */
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/* x is INF or NaN */
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if(ix>=0x7ff00000) return x*x;
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if(ix>=0x7ff00000) return x*x;
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/* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
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/* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
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if(ix<0x3fd62e43) {
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if(ix<0x3fd62e43) {
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t = expm1(fabs(x));
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t = expm1(fabs(x));
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w = one+t;
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w = one+t;
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if (ix<0x3c800000) return w; /* cosh(tiny) = 1 */
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if (ix<0x3c800000) return w; /* cosh(tiny) = 1 */
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return one+(t*t)/(w+w);
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return one+(t*t)/(w+w);
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}
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}
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/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
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/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
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if (ix < 0x40360000) {
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if (ix < 0x40360000) {
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t = __ieee754_exp(fabs(x));
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t = __ieee754_exp(fabs(x));
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return half*t+half/t;
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return half*t+half/t;
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}
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}
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/* |x| in [22, log(maxdouble)] return half*exp(|x|) */
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/* |x| in [22, log(maxdouble)] return half*exp(|x|) */
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if (ix < 0x40862E42) return half*__ieee754_exp(fabs(x));
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if (ix < 0x40862E42) return half*__ieee754_exp(fabs(x));
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/* |x| in [log(maxdouble), overflowthresold] */
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/* |x| in [log(maxdouble), overflowthresold] */
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lx = *( (((*(unsigned*)&one)>>29)) + (unsigned*)&x);
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lx = *( (((*(unsigned*)&one)>>29)) + (unsigned*)&x);
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if (ix<0x408633CE ||
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if (ix<0x408633CE ||
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((ix==0x408633ce)&&(lx<=(unsigned)0x8fb9f87d))) {
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((ix==0x408633ce)&&(lx<=(unsigned)0x8fb9f87d))) {
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w = __ieee754_exp(half*fabs(x));
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w = __ieee754_exp(half*fabs(x));
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t = half*w;
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t = half*w;
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return t*w;
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return t*w;
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}
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}
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/* |x| > overflowthresold, cosh(x) overflow */
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/* |x| > overflowthresold, cosh(x) overflow */
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return huge*huge;
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return huge*huge;
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}
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}
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#endif // ifdef CYGPKG_LIBM
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#endif // ifdef CYGPKG_LIBM
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// EOF e_cosh.c
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// EOF e_cosh.c
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